Search results for " medio ambiente"
showing 10 items of 967 documents
Tecnología de biorreactores anaerobios de membrana (AnMBR) para tratamiento de aguas residuales urbanas y reutilización de agua en agricultura. Una s…
2018
La combinación de la tecnología de biorreactores anaerobios de membrana (AnMBR, por sus siglas en inglés) para el tratamiento de aguas residuales y la reutilización de su efluente en agricultura da como resultado un concepto más sostenible para la depuración, donde las aguas residuales se convierten en una fuente de energía (biogás) y nutrientes (nitrógeno y fósforo) a la vez que se genera un recurso alternativo de agua que puede ayudar a paliar la escasez a la que nos enfrentamos a nivel global. Sin embargo, para aprovechar los beneficios del agua regenerada y los recursos recuperados de las aguas residuales se necesitan políticas inteligentes que brinden flexibilidad para la implementació…
La geografía en la E. G. B: Un ejemplo de descoordinación entre programas renovados y libros de texto
1985
Este trabajo explica el sentido que ha de tener la Geografía en la E.G.B. y los contenidos a estudiar según los Programas Renovados, por un lado; y el enfoque y contenidos de la Geografía que hay que estudiar según los libros de texto, por otro. A través del análisis de las distintas capacidades y contenidos que se plantean, se observa: 1.º Que la Geografía presentada por los Programas Renovados no se adapta plenamente a las exigencias de la sociedad y realizadas actuales; 2.º Que existe una descoordinación entre Programas Renovados y libros de texto; 3.º Que los libros de texto no trabajan aquellos objetivos para los que sus autores afirman que han sido editados. Por tanto, podremos utiliz…
El problema de la generación de residuos urbanos entre los contenidos de geografía de la enseñanza secundaria obligatoria
2002
Una de las características del problema de los Residuos Urbanos en nuestro país es la escasa conciencia ambiental de los ciudadanos. En este trabajo se exponen las grandes posibilidades que ofrece el currículo del Área de “Ciencias Sociales, Geografía e Historia” de la Enseñanza Secundaria Obligatoria (E.S.O.) para llevar a cabo acciones de Educación Ambiental, destacando así la capacidad de los profesores de Geografía para intentar mejorar la situación actual. Solid wastes generation problem into Secondary School Geography´s contents Citizenship’s low environmental conscience is a characteristic of Solid Wastes situation in Spain. In this paper, “Social Sciences, Geography and History” cur…
Unveiling microbial structures during raw microalgae digestion and co-digestion with primary sludge to produce biogas using semi-continuous AnMBR sys…
2020
[EN] Methane production from microalgae can be enhanced through anaerobic co-digestion with carbon-rich substrates and thus mitigate the inhibition risk associated with its low C:N ratio. Acclimated microbial communities for microalgae disruption can be used as a source of natural enzymes in bioenergy production. However, co-substrates with a certain microbial diversity such as primary sludge might shift the microbial structure. Substrates were generated in a Water Resource Recovery Facility (WRRF) and combined as follows: Scenedesmus or Chlorella digestion and microalgae co-digestion with primary sludge. The study was performed using two lab-scale Anaerobic Membrane Bioreactors (AnMBR). Du…
Modelling the metabolic shift of polyphosphate-accumulating organisms
2014
Enhanced biological phosphorus removal (EBPR) is one of the most important methods of phosphorus removal in municipal wastewater treatment plants, having been described by different modelling approaches. In this process, the PAOs (polyphosphate accumulating organisms) and GAOs (glycogen accumulating organisms) compete for volatile fatty acids uptake under anaerobic conditions. Recent studies have revealed that the metabolic pathways used by PAOs in order to obtain the energy and the reducing power needed for polyhydroxyalkanoates synthesis could change depending on the amount of polyphosphate stored in the cells. The model presented in this paper extends beyond previously developed metaboli…
Fate of endocrine disruptor compounds in an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor
2018
[EN] The occurrence and fate of three groups of micropollutants - alkylphenols, pentachlorophenol and hormones - were studied in a pilot plant consisting of an anaerobic membrane bioreactor (AnMBR) coupled to an activated sludge reactor (University of Cape Town configuration - UCT). Under anaerobic conditions, the octylphenol and technical-nonylphenol soluble concentrations increased producing negative degradation ratios (i.e., -175 and -118%, respectively). However, high 4-n-nonylphenol and bisphenol-A degradation ratios (92 and 59% for 4-n-nonylphenol and bisphenol-A, respectively) as well as complete pentachlorophenol, estrone, 17 beta-estradiol and 17 alpha-ethinylestradiol removal were…
Removal and fate of endocrine disruptors chemicals under lab-scalepostreatment stage. Removal assessment using light, oxygen and microalgae
2013
[EN] The aim of this study was to assess the effect of light, oxygen and microalgae on micropollutants removal. The studied micropollutants were 4-(1,1,3,3-tetramethylbutyl)phenol (OP), technical-nonylphenol (t-NP), 4-n-nonylphenol (4-NP), Bisphenol-A (BPA). In order to study the effect of the three variables on the micropollutants removal, a factorial design was developed. The experiments were carried out in four batch reactors which treated the effluent of an anaerobic membrane bioreactor. The gas chromatography mass spectrometry was used for the measurement of the micropollutants. The results showed that light, oxygen and microalgae affected differently to the degradation ratios of each …
A review on anaerobic membrane bioreactors (AnMBRs) focused on modelling and control aspects
2018
[EN] The use of anaerobic membrane bioreactor technology (AnMBR) is rapidly expanding. However, depending on the application, AnMBR design and operation is not fully mature, and needs further research to optimize process efficiency and enhance applicability. This paper reviews state-of-the-art of AnMBR focusing on modelling and control aspects. Quantitative environmental and economic evaluation has demonstrated substantial advantages in application of AnMBR to domestic wastewater treatment, but detailed modelling is less mature. While anaerobic process modelling is generally mature, more work is needed on integrated models which include coupling between membrane performance (including fouli…
Experimental sulphide inhibition calibration method in nitrification processes: A case-study.
2020
[EN] Sulphide is one of the inhibitors in the nitrification process in WWTP in regions with sulphate rich soils. As little information is currently available on sulphide nitrification inhibition, the aim of this study was to develop a method based on a modification of the Successive Additions Method to calibrate the effect of sulphide on the activity of ammonia-oxidising bacteria (AOB) and nitrite-oxidising bacteria (NOB). The developed method was then applied to activated sludge samples from two WWTPs with different influent sulphide concentrations. In both cases, sulphide had a greater inhibitory effect on NOB than AOB activity. The sulphide inhibition was found to be lower in the activat…
Treatment of a submerged anaerobic membrane bioreactor (SAnMBR) effluent by an activated sludge system: the role of sulphide and thiosulphate in the …
2014
This work studies the use of a well-known and spread activated sludge system (UCT configuration) to treat the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) treating domestic waste-water. Ammonia, phosphate, dissolved methane and sulphide concentrations in the SAnMBR effluent were around 55 mg NH4-N L-1, 7 mg PO4-P L-1, 30 mg non-methane biodegradable COD L-1, and 105 mg S2- L-1 respectively. The results showed a nitrification inhibition caused by the presence of sulphur compounds at any of the solids retention time (SRT) studied (15,20 and 25 days). This inhibition could be overcome increasing the hydraulic retention time (HRT) from 13 to 26 h. Among the sulphur compounds, …